Police Citizen Encounters

The Supreme Court has placed police-citizen encounters into three tiers
or categories:

First, there are communications between officers and citizens that are consensual and
involve no coercion or restraint of liberty. Such encounters are outside the scope of the Fourth Amendment. A person is
not seized within the meaning of the Fourth Amendment, however, merely because a law-enforcement officer approaches and
asks a few questions. A seizure occurs only when, taking into account all the circumstances, the law-enforcement
officers' conduct would have communicated to a reasonable person that he or she was not free to ignore the police
presence and go about his or her business.

Second, there are the so-called Terry-type stops. These are
brief, minimally intrusive seizures but which are considered significant enough to invoke Fourth Amendment safeguards
and thus must be supported by a reasonable suspicion of criminal activity. During a second-tier encounter, the police officer
actually conducts a brief investigative stop of the citizen. In this level, a police officer, even in the absence of
probable cause, may stop persons and detain them briefly, when the officer has a particularized and objective basis for
suspecting the persons are involved in criminal activity. To stop a citizen, the officer must possess more than a
subjective suspicion or hunch. The officer's action must be justified by specific facts which, taken together with
rational inferences from those facts, reasonably warrants that intrusion, and the detention cannot be either arbitrary
nor harassing. In short, an investigatory stop must be justified by some objective manifestation that the person
stopped is, or is about to be, engaged in criminal activity.

Third, there are highly intrusive,
full-scale arrests, which must be based on probable cause. Probable cause exists when the arresting officer has
knowledge or reasonably trustworthy information sufficient to warrant a person of reasonable caution in the belief that
an offense has been committed by the person to be arrested.